Mast and spar of yachts and other craft



Aug. 15, 1950 H. CRANKSHAW nus-r AND Sm; 0F mom's AND OTHER- CRAFTFiled, April 19, 1946 IINVENTOR z g kMcr'mksmw Patented Aug. 15, 1950 72,519,230 "EMAs'r AND SPAROF YACHTS AND OTHER v. T. Hugh M. Crankshaw,Moseley, Birmingham, 4 l England 1 Application April 1'9;1946, SerialNo. 663,485 l n F e In Great Britain June 26, 1945 My invention isconcerned with improvements to sayrin the case of a mast from the headto the:-

in; orzrelating to the masts and spars of. yachts. heel or foot thereof;1 or the taper formation of I and other craft provided with sail, thesaid imthe said channel-like partsv may be such that provements havingfor their object to simplify the mast or spar has a maximum diameter ator, and economise the manufacture ofthe said about the middle partthereof and tapers to-v masts and spars and further. to provide mastsWards its respective ends.

and spars which while being of ample strength Or instead of the crosssectional shape of the are-considerably lighter inweight than thefimastssemi-tubular or channel-like complementary andspars of equivalent lengthas ordinarily conparts being such as to provide a mast of circularstructed. l. .7 10 figure in cross section the crosssectional shape- Myinvention resides in a mast or sparchare of the complementary part maybe such as to acterised in that it is constructed from or 111- provide amast of other cross sectional shape; corporates a pluralityofsymmetrical and com- A continuous plate, or a plurality of platesarplementary, parts or sections of; a semi tubular ranged end to end maybe interposedbetween or channel-like formation which may be fabrithecomplementary semi-tubular or channel-likecated by rolling or pressingoperations from parts, ,thesaid plate or plates being disposed diaplatesor sheets of stainless steelor any suitable metrically.acrosstheinteriorandextending preilight metallic alloy or aplastic substance havingerably from head to heel, or end to end of the thegtensile strength andother properties mast or spar and serving to give increased requisitefor withstanding the stresses to which rigidity and strength to thestructure.

such masts and sparsare subjected in-use, each Myinvention will befurther and more par-- semi-tubular or channel-like part or sectionbeticularly described with reference-to the accoming formed along itsrespective longitudinal edges panying drawings as applied to theconstruction with an outwardly directed flange-like part, the of a mastand wherein two tubular sections are corresponding flange-like parts onthe comple- .comprised in the mast structure.

mentaryisections being, when the sections are Figure 1 represents themast in elevation. assembled to constitute the mast orspar, securedviewed, from the starboard side, considerable togetherby rivetting or bya Welding operation. portions thereof being broken away intermediate Inthe application ofthe inventionto masts the top and heel, in consequenceof the limitathe connected flange-like parts are disposed on 3() tionsimposed on the length of the sheet pre the fore and aft sides of themastwhen erected cribed forthe drawings. i r and along theafter flangesofthe semietubular Figure 2 is a similar view of afragmentarydrgchanrielelike'sectionsa runner or trackproportion of thevmast withparts thereof herein-- vided for the rings and tackle associated withthe after more particularly referred to, broken away lufl of the sailfor its seizing and raising or '10W-' 5 v Figure 3 is an after sideelevation of a frager'ing 'on the mast. mentary portion of the saidmast.

j Where the mast orfspa'r'is of moderate 1ength,' Figure 4 is asectional planon the plane indisay up to feet, two only of the saidsemi-tubucated by the dotted line 4-4, Figure 1. lar or channel-like andcomplementary parts Figure 5 is a similar view to Figure 2 illustratmaybe employed in its construction; but where ing a further mastconstruction hereinafter more the mast or spar exceeds 30 feet inlength, or particularly described. even if desired where it is of lesslength than 30. Figure 6 is a sectional plan on the plane indifeet, itmay be constructed. from a plurality of cated by the dotted line E6,Figure5, the lower tubular sections each constituted bya pair of theportion of the said Figure 6 being broken. away. said flangedsemi-tubular or channel-like com-' 5. Figure 7 illustrates amodificationin the cross plementary parts, the tubular sectionsrequisite sectional shape of the semi-tubular or channelfor obtainingthe desired length in the mast or like parts employed in theconstruction of masts: spar being assembled and connected endto end orspars" in accordance with my invention. in axial alignment. V V Inthesaiddrawings the two tubular sections 'The complementary semi-tubularor channel- 5; comprisedin'the mast are denoted, in therelevalike partsmay be so shaped incross section as to tional'vi'ews by thereferences Aand B, therefer-j produce a mast or spar having a circular or subence Adenoting the upper and the referenceB stantially circular figure incross section, and the lower section respectively of the structure.tapering from a maximum diameter at one end 1 Each of thesetubularsections is constituted he in i ms sfei s P es? an ins ii b WP smmetr al-end .qem sm nieer s e -5 nel-like parts marked in therespective sections with the references a, a and b, b, the saidcomplementary parts being formed on their respective side edges with anoutwardly directed flange, the flanges on the section A being denoted bythe references a a and those on the section B by the references 11 ,17

Thesefl'anges may, a's'shown; be provided with perforations for thepassage therethrough of rivets whereby the two channel-like parts com-:

prised in each section are secured. to each other to form the tubularsections. 7

Alternatively, where the masts are, as is preferable, formed from metal,the securing of the two channel-like parts together may be effected bywelding them at the flanged portions. a a

b b thereof. r The sections A, B taper gradually from their lower totheir upper ends, the lower end of the section A being of a diameterproper to take and fit into the upper end of the section Band beingadapted: for thi'sengagement -bythe cutting away of the lower endportions of itsflanges a a so as thereby to leave an unflanged semi-tubular ex-- tension at on each channel-like. part a, these extensionsa when located'inthe upper: end of the section B; bein fixed therein byWelding or rivetting. I

A s-pli-tring, not shown, may if desired be in-- troduced into the lowerend of the upper section A, the said split ring which serves toreinforce the mast structure at thisj-unction of the: tubular sectionsA, B, fitting against the inner periphery ofthe parts a and being fixedthereto-by rivet-- ting or welding;

The mast is erected withthe flanges: a b and a; b disposed 'respectivelyon the fore and aft presented sides thereof.

The flanges a b on the aft presented side, as shown in Figs. 2 and l,are-made somewhat wider than the flanges a b on the fore side, and thesaid afterside flange on each semi-tubular or channel-like section iscurved or bent laterally outwards from the vertical longitudinal planecontaining the axis of the: mast, the said outwardly' turned parts,markeota; b on the respective sections a, b, co-actingto provideintegral with the mastthe runner or track for the ringsand tackleassociated with the luff of the sail for its seizing and raising andlowering onthe mast.

A plate (2 is interposed bet'ween the symmetri'-- cal andcomplementarychannel-like sections for the purpose of givingrigidity tothe mast structure; the said plate being disposed in: the middlelongitudinal plane of the mast, its fore and aft edges, as shown inFigs. 2- and 4; being located between the fore and aft flanges:respectively of the channel like sections and being; securedtherebetweenin the rivettingor weldingoperae tiodemplbyed for effecting, theconnecting together of the complementary channel-like sec-- tions'embodied in the mast structure.

The reinforcing plate 12 may, if the length of" the mast isnot'. too.great as to render it inconveni'ent or impracticable, be continuousplate extending from the heel to .the topof the mast. or through anydesired portion of the length of the mast, but when the length; of the:mast is'such as to. render the employment of asingle or continuous plateinconvenient or impracticable a plurality of plates arranged end to endmay be employed in the structure of the mast.

As shown in Figs..5 and 6, the runner'or track provided" on theaftersi'de' of the mast for the purposespecified', is formed as anintegralpart of 4 the mast by the incorporation in the mast structure ofa bar e of metal or a suitable plastic substance, the said bar which mayconveniently be formed by an extrusion process, being located betweenthe flanges a b on the aft presented edges of the complementarychannel-like section and fixedgthereto' by'rivets as shown, or otherwisefixed thereto.

The said bar e is provided on each face thereof which is external to thetubular body of the mast, and is presented aft, with a laterallydirected part or flange e the said flanges giving to the bar at thislongitudinal side thereof a T-section in formationtoaffordithe runner ortrack on the mast. The bar e may be continuous or it may be in sectionsof suitable length according to the height of the mast to beconstructed, and, as

shown in Figs. 5 and 6, the mast structure incorporates a diametricallydisposed reinforcing plate d, which may also be continuous or insections: as. aforesaid, the: inner or forwardly presented; edge of the.bar e, or its sections, as the. case may be; being formed; with 2. parteof channel-like. formation. and. wherein the. after edge of. thediametrical plate.- d, or plate sections, is lo.-- cated. and fixed byrivets 1?, orotherwise fixed. therein.

By this construction the flanges provided: at the respective sides ofthe complementary channel'- like sections for effecting their attachmentto eachother can be of the same width at both sides thus facilitatingthe-production of the said sec tions by rollingoperations. Further, thiscon-- 7 struction permits the ready provision of a runner or track ofthedimensions required for any sizeof mast and considerably enhances therigidity'of' them-ast structure;-

Instead'ofthec-rosssectional shape of the com-- plementary semi-tubularor channel-like sections embodied in the mast structure being such as toprovide a mast of circular figure in cross section their cross sectionalshape may be such that the tubular mast formed thereby will have a pearoregg-likeshape in cross section, such for example asis illustrated inFigure 7-, the narrow part taking a streamline form, and further thesaid sections may be so taperedi'n the direction of their length thatthe" mast will be of greatest cross sectional dimensions at a partthereof intermediate its respective ends. 7

The application of the invention to the. construction of spars differsin no essential respect from itsapplication to masts'as hereinbeforedescribed.

By the improved construction. of masts and spars described not only istheir manufacture considerably simplified and economised. but, their useconsiderably reduces top weight, thus lowering the centre of gravity andincreasing the stability of the vessels. in which they are provided. andfurther in the case of racing craft. they allow the use of a longermastthan with masts. of ordinary construction, thus. increasing sailarea and. giving more speed.

I claim:

A tubular. mast. for sailing craft, comprising two symmetrical andcomplementary semi-tubular sections formed along their longitudinaledges with outwardly directed flanges, the flanges on each section beingsecured to the flanges. on theother section, oppositely directedrunners. extending along, the flanges at one side of the mast andproviding a track for the travel of luff rings and. tackle. of a saillsaidtrack being constituted by a. bar-like member located and fixedbetween the flanges of said sections, a portion of said bar beingexternal to the tubular mast and having flanges at its opposite sidesand having a substantially T-shaped cross section which provides saidtrack, and said bar-like member having an inner longitudinal edge Withinthe mast formed with a groove, and a reinforcing plate disposeddiametrically of said sections and secured between flanges thereof andhaving an edge within 6 REFERENCES CITED The following references are ofrecord in the file of this patent:

the mast fixed in the groove of said bar-like 10 2,122,330

member.

HUGH M. CRANKSHAW.

5 UNITED STATES PATENTS Number Name Date 564,627 Leyner July 28, 18961,691,818 Kraft Nov. 13, 1928 1,930,285 Robinson Oct. 10, 1933 Ragsdaleet a1 June 28, 1938 FOREIGN PATENTS Number Country Date 396,745 GreatBritain Aug. 3, 1933

